Stats out of Syria Clouded by Chaos of War

In the debate over how to respond to the chemical attacks in Syria, numbers have been central: the number of people killed; the proportion of rebel fighters who are allied with al Qaeda; the percentage of people world-wide who oppose the use of chemical weapons.

Some of these figures have been difficult to estimate in a chaotic war zone, and have been hotly disputed. Many come from parties that may tweak the counts for their agendas, said Anthony H. Cordesman, a military analyst at the Center for Strategic and...